Since the inception of this project on September 1, 1972, we have developed a technology suitable for the noninvasive measurement of pulmonary ventilation and perfusion. This is based on electronic sampling devices and computer analysis which allow us to measure the small incremental density change in the lungs that is associated with each cardiac systole. This technique is totally noninvasive with respect to the patient, and the patient has no discomfort. Our initial human experimental work has confirmed that primary and secondary malignant tumors of the lung cause marked changes in the pulmonary densitometric pulsation. During the current funding period of this grant, we will begin some clinical trials to evaluate this screening technique with regard to differentiating primary and secondary lung malignancies, and to differentiate lung malignancies from granulomas. Included in this group of evaluations will be a protocol for estimating the earliest point of detection that can be achieved using videodensitometry for screening in lung cancer. BIBLIOGRAPHIC REFERENCES: Reinke, R.T., Silverman, N.R., Rosen, L., Hellend, D.R. Pulmonary videodensitometry in the diagnosis of carcinoma of the lung. Radiology 118:521-525, March 1976. Higgins, C.B., Hellend, D.R., Rosen, L., Silverman, N.R. Velocity of left ventricular wall motion determined by fluoroscopic videodensitometry: A noninvasive method for evaluating myocardial contractile state. Invest. Radiol. 11:24-31, Jan.-Feb. 1976.